CN104009465B - A kind of digital current-sharing method of dereliction decentralized DC power system - Google Patents

Abstract

The invention discloses a kind of digital current-sharing method of dereliction decentralized DC power system.After each power module of the present invention obtains the running parameter of other power module, running parameter in conjunction with self calculates Rate of average load, current correction amount, average control channel response speed and the proportional gain of current voltage ring controller, it is achieved the renewal of the proportional gain of current correction amount and Voltage loop controller.The present invention uses CAN or I²C bus communication mode, particularly I²C bus can be supported by most microprocessors, there is high performance-price ratio, each power module status is impartial, supports " N+m " Redundancy Design, if wherein certain power module failure, on the output of whole parallel system without impact, and trouble power replacement can be carried out online, can realize that there is identical output voltage, but the power module of different capacity grade is in parallel, and when the big change of load, there is preferable dynamic current equalizing characteristic, the highest to the rate requirement of data communication.

Description

A kind of digital current-sharing method of dereliction decentralized DC power system

Technical field

The present invention relates to the equal Flow Technique of the high power system that multiple DC power supplier forms in parallel, be specifically related to A kind of digital current-sharing method of dereliction decentralized DC power system.

Background technology

In high-power DC power supply electric power system, the power module parallel connection often using multiple smaller power is defeated to realize big electric current Going out, combination meets different capacity demand in parallel, easily realizes standardized production, obtains highly reliable also by redundancy backup Property ensure.Due to factors such as technological level, component parameter difference and temperature drifts, even if using the power module of same model only to lead to Cross simple parallel connection and do not accomplish that current-sharing exports.The power module that load current is big will shorten the life-span, domino effect even occurs, Accelerate the damage of whole power-supply system.All Flow Technique are the key technologies realizing distributed power supply module parallel operation, and good is equal Stream does not require nothing more than each power module and has close electric current in load constant timing, and can be with close when load dynamically change yet The change of speed follower load, it is achieved dynamic current equalizing.

Digital current-sharing is the global information using data communication technology to obtain parallel power supply system, gives each electricity according to the requirement of current-sharing Source module distribution load current, makes each power module electric current equal finally by numerically controlled method.Digital current-sharing is because of it Need element less, affected by environment less and the advantages such as complex control can be realized and paid attention to.But, available data current-sharing skill Art has a disadvantage in that it is generally required to external equalizing controller completes collection and the distribution of the current data of each module, the most external Controller failure, whole power-supply system will lose current balance function；The information obtained by data communication only has current information, current-sharing Algorithm is excessively simple, mainly based on Current for paralleled (stable state current-sharing), does not accounts for the dynamic characteristic of each power module (temporarily Step response) difference.

Summary of the invention

For the deficiencies in the prior art, the present invention provides a kind of digital current-sharing method of dereliction decentralized DC power system, specifically Technical scheme is as follows.

A kind of digital current-sharing method of dereliction decentralized DC power system, described DC power system uses N number of power module to lead to Cross composition in parallel, between each power module, use CAN or I²C bus communication connects, and each power module is one Node, each power module operation principle is identical, and the job step of each power module includes:

1) each power module broadcasts the message bag of this node, and each power module receives other power modules in DC power system The message bag sent, described message includes the transmission power module address of power module of this message bag, duty, maximum Allowable current, current flow and current control channel response speed.

2) each power module use voltage control loop be outer shroud, current regulator be the double-loop control mode of inner ring, all use PI director mode.Each power module calculates averagely according to maximum permissible current value and the present current value of each power module Load factor, then calculates respective current correction amount I according to the Rate of average load of gained_adj.By current correction amount I_adjWith Voltage loop PI The output I of controller_coPhase adduction obtains current reference value I after amplitude limit_ref, electric current loop PI controller regulation output electric current makes it reach To I_ref.The response speed of the time Δ T reflection electric current loop needed for regulation process, Δ I_refFor current change quantity, calculate this module accordingly Control channel response speed.Each power module calculates power-supply system according to the channel response speed that controls of all power modules Average control channel response speed；Each power module calculates each according to the average control channel response speed of gained power-supply system Voltage loop PI controller gain.

3) each power module updates respective electricity according to above-mentioned calculated current reference value and Voltage loop PI controller gain Stream reference value and Voltage loop PI controller gain.

4) circulation above-mentioned steps 1) to step 3) realize the digital current-sharing method of dereliction decentralized DC power system.

It is further preferred that each power module has unique 7 bit address codes, when using CAN communication, power supply 7 bit address codes of module embed in the ID of CAN message frame, identify the sender of data accordingly；When using I²During C bus communication, 7 bit address codes of power module are sent, for power module identification, I after the broadcast address of message bag²C bus saves Point switches in main frame-transmitter mode with between machine-receiver mode, when needs send data, is in main frame-transmitter mould Formula, after sending data, switches back immediately to from machine-receiver mode.

It is further preferred that step 1) in data field in the message bag that sends of each power module include the work of power module Make state, maximum permissible current, current flow, control channel response speed, wherein by 1 byte representation duty, use 2 byte representation maximum permissible currents, with 2 byte representation current flow, control channel response speed with 2 byte representations.

Further, step 2) in the Rate of average load of each power module be:

Further, step 2) described in the current correction amount of each power module be:

Wherein I_goalMaximum permissible current-the I of (k)=Rate of average load × each module_t, I_tFor power module current flow, k represents kth time Calculating, k-1 represents kth and calculates for-1 time, I_adjFor current correction amount.

Further, step 2) described each power module respective average control channel response speed is:

Wherein N is the number of the power module forming DC power system.

Further, step 2) described each power module respective Voltage loop PI controller gain is:

$K_u=\left\{\begin{array}{c}{K}_{u\min },K_{\mathrm{ugoal}}\≤K_{u\min }\\ K_{\mathrm{ugoal}}\\ K_{u\max },K_{\mathrm{ugoal}}\≥K_{u\max }\end{array}\right.$

Wherein K_uFor Voltage loop PI controller gain, K_ugoalThe maximum permissible current of=average control channel response speed × module, K_uminWith K_umaxThe conventional methods such as critical proportionality range are used to determine.

Further, step 2) described in Voltage loop PI controller output electric current after each self-adjusting of each power module be:

$I_{\mathrm{co}}=K_u(V_e\left(t\right)+\frac{1}{T_u}{\∫}_0^t{V}_e\left(t\right)\mathrm{dt})$

Wherein parameter T_uUse for the time of integration conventional methods such as critical proportionality range to determine, immobilize after determining, I_coFor Voltage loop PI Controller output electric current, V_eFor voltage error, K_uFor Voltage loop PI controller gain.

It is further preferred that communicate to connect according to CAN between each power module of described DC power system, then CAN needs to connect the impedance of 2 couplings；According to I between each power module of described DC power system²C bus communication is even Connect, then I²Two transmission line SCL and SDA of C bus are required for connecting pull-up resistor, and the value of pull-up resistor is N × 4.7K Ω, Wherein N is the number of described DC power system parallel electric source module.

The parallel power supply system of the present invention does not set equalizing controller, and each power module status is equal, for dereliction decentralized current-sharing side Method, without the concentration of risk problem of equalizing controller.The work that each power module obtains other power module by digital communication is joined After number (including duty, maximum permissible current, current flow and control channel response speed), the work in conjunction with self is joined Number calculates Rate of average load, current correction amount, average control channel response speed and the proportional gain of current voltage ring PI controller, And realize the renewal of the proportional gain of current correction amount and Voltage loop PI controller, reach good stable state current-sharing and transient response.Root Reference current and proportional gain is updated, it is possible to achieve there is the power supply mould of identical output voltage, different capacity grade according to load factor Block is in parallel.

Compared with prior art, the present invention has the advantages that:

(1) CAN or I are used²C bus realizes dereliction digital current-sharing, communicates reliable and stable, particularly I²C bus Can be supported that there is the highest cost performance by microprocessors such as most MCU and DSP.

(2) each power module status is impartial, without master-slave, supports " N+m " Redundancy Design, if wherein certain power module Fault, then automatically exit from and report to the police, and on the output of whole parallel system without impact, and can carry out trouble power replacement online.

(3) can realize having identical output voltage, but the power module of different capacity grade is in parallel, and in the big change of load Time, there is preferable dynamic current equalizing transient performance, and the highest to the rate requirement of data communication.

Accompanying drawing explanation

Fig. 1 is dereliction decentralized DC power system block diagram based on CAN；

Fig. 2 is based on I²The dereliction decentralized DC power system block diagram of C bus；

Fig. 3 is the control principle drawing of single power module；

Fig. 4 is sharing control algorithm flow schematic diagram.

Detailed description of the invention

Below in conjunction with the accompanying drawings the detailed description of the invention of the present invention is illustrated, but the enforcement of the present invention and protection are not limited to this.

Fig. 1 and Fig. 2 sets forth employing CAN and I²The dereliction decentralized DC power system block diagram of C bus.Use CAN needs to connect the impedance of 2 couplings, lays respectively at the two ends of two transmission line CAN_H and CAN_L, typically takes 120 Ω Resistance；I²Two transmission line SCL and SDA of C bus are required for connecting pull-up resistor, and the span of pull-up resistor is relatively wide, Can take N × 4.7K Ω, wherein N is the number of parallel electric source module.

Tables 1 and 2 sets forth employing CAN and I²The message packet format of C bus, address field format is different, with Just be suitable for respective data link layer standard, and data field use identical form, include duty (1 byte), Maximum permissible current (2 byte), current flow (2 byte), control channel response speed (2 byte).Use I²C is total During line, I²C peripheral hardware is set to, from machine-receiver state, receive the broadcast that in bus, other node is sent at ordinary times, and this A little data are saved in a tables of data；Periodically or time oneself state changes, transfer main frame-transmitter status to, the machine Data packet broadcast in bus, be sent, transfer to immediately from machine-receiver state.It is not required to carry out shape during CAN communication State switches, CAN controller be automatically transmitted and receive.

Table 1

Table 2

With reference to Fig. 3, the control system of power module use voltage control loop be outer shroud, current regulator be the double-loop control of inner ring System, the controller PI of Voltage loop_uController PI with electric current loop_iAll use PI controller.Steady-state current current-sharing is by regulation electricity The current reference value of stream inner ring realizes, and transient current current-sharing is realized by the proportional gain of regulation Voltage loop controller.Module M501 is the DC/DC converter of power module, is to realize the power conversion circuit that voltage and current controls.Module M502 is Current loop controller, proportional gain and the parameter time of integration of its PI controller determine when dispatching from the factory, solid during sharing control Fixed constant.Therefore, current loop controller can use the method for numeral or simulation to realize.Module M503 is Voltage loop control Device, shown in form such as formula (1).

$I_{\mathrm{co}}=K_u(V_e\left(t\right)+\frac{1}{T_u}{\∫}_0^t{V}_e\left(t\right)\mathrm{dt})---\left(1\right)$

In formula (1), I_coElectric current, V is exported for Voltage loop_eFor voltage error；T is time variable, parameter K_uAnd T_uBe respectively than Example gain and the time of integration, the conventional methods such as critical proportionality range can be used to determine, the time of integration T_uImmobilize after determining；And Proportional gain K_uAt K_uminAnd K_umaxBetween change.By regulation K in dynamic current equalizing control_uRegulate the response speed controlling passage Degree.Module M504 is that the current reference value to electric current loop carries out amplitude limit so that it is in the current range that power module is allowed, it is to avoid Cross stream.Module M505 is the key modules of current-sharing, and it calculates current correction amount I_adjPI with Voltage loop_uThe ratio of controller increases Benefit.First, Rate of average load is calculated, such as formula (2) according to the maximum permissible current and current flow collecting each power module come Shown in.

According to Rate of average load calculating current correcting value, as shown in formula (3).

Wherein I_goal(k)=Rate of average load × maximum permissible current-I_t, k and k-1 represents this and previous correlation computations (generation the most respectively respectively Table kth and k-1 calculating).Formula (3) ensures that the correction of the electric current loop reference value every time calculated will not be excessive.Pass through I_adj's Amendment has reached amendment current reference value I_refPurpose, revise I_refAfterwards, regulation output electric current is reached I by electric current loop_ref, The time of regulation process reflects the response speed of electric current loop, Δ I_refFor current change quantity, the time needed for Δ T change, definition electricity Stream ring response speed and control channel response speed are formula (4) and formula (5).

Control channel response speed=electric current loop response speed × K_u (5)

Module M505 calculates average control channel response speed according to controlling channel response speed, and such as formula (6), wherein N is Parallel electric source module number.

The proportional gain of the PI controller of Voltage loop is calculated, such as formula (7) and formula (8) institute according to average control channel response speed Show.

K_ugoal=average control channel response speed × maximum permissible current (7)

$K_u=\left\{\begin{array}{c}{K}_{u\min },K_{\mathrm{ugoal}}\≤K_{u\min }\\ K_{\mathrm{ugoal}}\\ K_{u\max },K_{\mathrm{ugoal}}\≥K_{u\max }\end{array}\right.---\left(8\right)$

Formula (8), on the premise of ensureing stability, regulates the response speed of each module, the sound of the module that maximum permissible current is bigger Answer speed fast.

The total control flow schematic diagram of this example is as shown in Figure 4.Step S601, first power module broadcast the packet of this node, CAN and I2C bus are all according to priority transmitted according to loss arbitration.Step S602, receives the joint of other power module Point data bag, and the relevant parameter preserving and updating in self tables of data.Step S603, calculates Rate of average load and electric current school Positive quantity, and then obtain the output electric current of this node.Step S604, calculates average control channel response speed, calculates Voltage loop The proportional gain of PI controller.Step S605, updates current reference value and Voltage loop controller gain.Owing to have employed restrictor ring Joint and dynamic current equalizing measure, reduce the requirement to data communication rates, and the data update cycle, in second level, is typically set to 1 Second.This algorithm both ensure that stable state current-sharing, has again consistent dynamic response characteristic.

Claims (9)

1. the digital current-sharing method of a dereliction decentralized DC power system, it is characterised in that described DC power system uses N Individual power module is constituted in parallel, uses CAN or I between each power module²C bus communication connects, Mei Ge electricity Source module is a node, and the operation principle of each power module is identical, and the job step of each power module includes:

1) each power module broadcasts the message bag of this node, and each power module receives other power modules in DC power system The message bag sent, described message includes the transmission power module address of power module of this message bag, duty, maximum Allowable current, current flow and current control channel response speed；

2) each power module use voltage control loop be outer shroud, current regulator be the double-loop control mode of inner ring, each power supply Module calculating Rate of average load the Rate of average load according to gained calculate current correction amount I of this module_adj, by current correction amount I_adj Output I with Voltage loop PI controller_coPhase adduction obtains current reference value I after amplitude limit_ref, the regulation of electric current loop PI controller is defeated Go out electric current and reach I_ref；The response speed of the time Δ T reflection electric current loop needed for regulation process, Δ I_refFor current change quantity, according to This calculates and controls channel response speed；Each power module calculates power supply system according to the control channel response speed of all power modules The average control channel response speed of system；Each power module is according to the average control channel response speedometer of the power-supply system of gained Calculate the PI controller gain of the Voltage loop of this module；The proportional gain of described each power module respective Voltage loop PI controller is:

$K_u=\left\{\begin{array}{cc}{K}_{umin},& K_{ugoal}\≤K_{umin}\\ K_{ugoal}& \\ K_{u\max },& K_{ugoal}\≥K_{umax}\end{array}\right.$

Wherein K_uFor the proportional gain of Voltage loop PI controller, K_ugoalThe maximum permissible current of=average control channel response speed × module, K_uminAnd K_umaxEmploying critical proportional band law determines；

3) each power module updates respective current reference value according to calculated current reference value and Voltage loop controller gain PI controller gain with Voltage loop；

4) circulation above-mentioned steps 1) to step 3) realize the digital current-sharing method of dereliction decentralized DC power system.

A kind of digital current-sharing method of dereliction decentralized DC power system, it is characterised in that Mei Ge electricity Source module has unique 7 bit address codes, when using CAN communication, 7 bit address codes of power module is embedded CAN and disappears In the ID of breath frame, identify the sender of data accordingly；When using I²During C bus communication, 7 bit address of power module are being disappeared Send, for power module identification, I after the broadcast address of breath bag²C bus node is in main frame transmitter mode with from machine Switch between receiver mode, when needs send data, be in main frame transmitter mode, after sending data, cut immediately Gain from machine receiver mode.

A kind of digital current-sharing method of dereliction decentralized DC power system, it is characterised in that step 1) In data field in the message bag that sends of each power module include the duty of power module, maximum permissible current, current Electric current, control channel response speed, wherein by 1 byte representation duty, with 2 byte representation maximum permissible currents, With 2 byte representation current flow, control channel response speed with 2 byte representations.

A kind of digital current-sharing method of dereliction decentralized DC power system, it is characterised in that step 2) The Rate of average load of each power module is:

The digital current-sharing method of a kind of dereliction decentralized DC power system the most according to claim 1, it is characterised in that step 2) the current correction amount of each power module described in is:

Wherein I_goalMaximum permissible current-the I of (k)=Rate of average load × each module_t, I_tFor power module current flow, k represents kth time Calculating, k 1 represents kth and calculates for 1 time, I_adjFor current correction amount.

The digital current-sharing method of a kind of dereliction decentralized DC power system the most according to claim 1, it is characterised in that step 2) described each power module respective average control channel response speed is:

Wherein N is the number of the power module forming DC power system.

The digital current-sharing method of a kind of dereliction decentralized DC power system the most according to claim 1, it is characterised in that

Step 2) described in the output electric current of Voltage loop PI controller after each self-adjusting of each power module be:

$I_{co}=K_u\left(V_e\right(t)+\frac{1}{T_u}{\∫}_0^t{V}_e(t\left)dt\right)$

Wherein parameter K_uAnd T_uIt is respectively proportional gain and the time of integration of Voltage loop controller；Variable I_coAnd V_eBe respectively output electric current and Voltage error.

The digital current-sharing method of a kind of dereliction decentralized DC power system the most according to claim 1, it is characterised in that described Communicate to connect according to CAN between each power module of DC power system, then CAN needs to connect 2 coupling resistances Anti-；According to I between each power module of described DC power system²C bus communication connects, then I²Two transmission of C bus Line SCL and SDA is required for connecting pull-up resistor, and the value of pull-up resistor is N × 4.7K Ω, and wherein N is described dc source system The number of system parallel electric source module.

The digital current-sharing method of a kind of dereliction decentralized DC power system the most according to claim 1, it is characterised in that described Voltage loop controller PI in double-loop control mode_uWith current loop controller PI_iAll use PI controller.